Standard Features - Easy to use - Straightforward display and basic buttons keep operation simple - Large, clear, backlit digital display - Easy to read in various lighting conditions - Auto change from heating to cooling - Temperature range limits - Set minimum cool and maximum heat temperature settings - Precise temperature control of +/-1 F to maximize comfort - Display Options C or F temperaturev - Easy-access battery replacement - Flip-out door for easy battery replacement without removing or disassembling the thermostat - Compatible with heating and cooling plus heat pumps - Does not work with electric baseboard heat (120-240V) - Model: RTHL3550D - 1-Year Warranty